Bariatric treatment system and related methods

ABSTRACT

A bariatric treatment system providing a comprehensive array of therapeutic services for the morbidly obese patient is disclosed. The treatment system generally comprises a stable bed frame upon which is mounted a low air loss therapeutic mattress system. Integrated hardware and software controls provide such therapies as pulsation, percussion, rotation, cardiac chair and Trendelenburg. Means are disclosed whereby the bariatric patient may safely and comfortably enter and exit the bed with relative ease. The bed is adaptable for transport within a hospital, including such features as a TRANSPORT MODE wherein the bed&#39;s lateral axis is minimized and battery backup to maintain necessary therapies during patient transport. A plurality of control means are disclosed for simplification of caregiver workload and ease of patient utilization.

RELATED APPLICATIONS

This Application is a continuation-in-part of Applicant's co-pendingU.S. patent application Ser. No. 10/351,711, filed Jan. 27, 2003, whichis a continuation of U.S. patent application Ser. No. 08/972,209, filedNov. 17, 1997, now U.S. Pat. No. 6,536,056, issued Mar. 3, 2003, whichin turn claims priority to U.S. Provisional Patent Applications Ser. No.60/031,666 filed Nov. 21, 1996 and Ser. No. 60/031,408 filed Nov. 18,1996, both now abandoned. This Application claims domestic priority,under 35 U.S.C. § 119(e)(1), to the earliest filing date of Nov. 18,1996.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to bariatric patient beds having apparatusand methods for monitoring and/or controlling therapeutic mattresssystems and the patients supported thereon and, more particularly, tosuch bariatric beds having features for facilitating the care, supportand comfort of the bariatric patient through monitoring of angulardeviations of the mattress surface and patient from the flat, horizontalposition and control of the mattress system in response thereto.

2. Description of Background Art

The treatment of morbidly obese, or bariatric, patients presents manychallenges heretofore not adequately addressed. These patients,typically weighing in excess of 500 pounds and often in the range of 500to 800 pounds, have previously been denied many of the availabletherapeutic modalities due primarily to the difficulties associated witheffecting such treatments in a treatment system capable of withstandingthese patients' great weights. The emphasis of previous systems has beento confront the obstacles concomitant handling of the bariatric patient;this focus has resulted in a void of developments for providingtherapeutic care for the bariatric patient.

It is therefore an overriding object of the present invention to improveover the teachings of the prior art in the provision of a plurality oftherapeutic services for the bariatric patient. It is further an objectof the present invention to provide these therapies on a safe,comfortable, efficient platform adaptable to a variety of circumstancesand treatment environments.

BRIEF DESCRIPTION OF THE DRAWINGS

Although the scope of the present invention is much broader than anyparticular embodiment, a detailed description of the preferredembodiment follows together with illustrative figures, wherein likereference numerals refer to like components, and wherein:

FIGS. 1, 2, 3, 4, 5, 6, 7, and 7A show various perspective views of thepreferred embodiment of the present invention, a bariatric treatmentsystem 100;

FIG. 8 shows the inflation structure 146 of the therapeutic supportsurface 104 of the bariatric treatment system 100;

FIGS. 9, 10, 11, and 12 show details of the bariatric treatment system'sblower and valve block assembly 137, including details of the valvecontrol motors 149;

FIGS. 13 and 14 show details of the bariatric treatment system'spercussor assemblies 160;

FIGS. 15A and 15B show a schematic overview of the hardware and softwarecontrol system 170 of the bariatric treatment system 100; and

FIGS. 16A, 16B, 16C, 16D, 17A, 17B, 17C, 17D, 17E, 18A, 18B, 18C, 18D,18E, 18F, 19A, 19B, 19C, 19D, 20A1, 20A2, 20B1, 20B2, and 21 showvarious detailed schematic diagrams of the various control boardsutilized in the preferred embodiment 100, each of which is specificallyreferenced in the specification which follows.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

By reference, the specifications of U.S. patent application Ser. No.08/672,442, filed Jun. 28, 1996, and U.S. patent application Ser. No.08/382,150, filed Jan. 31, 1995, are incorporated herein as if each werenow set forth in its respective entirety.

Although those of ordinary skill in the art will readily recognize manyalternative embodiments, especially in light of the illustrationprovided herein, this detailed description is exemplary of the presentlypreferred embodiment of the present invention, the scope of which islimited only by the claims appended hereto. The preferred embodiment ofthe present invention, a bariatric patient therapeutic treatment system100, generally comprises a treatment bed uniquely indicated forbariatric patients, i.e., patients weighing in excess of 500 pounds,commonly in the range of 500-800 pounds. The frame of the bed generallycomprises a base frame 101, a load frame 102 and various assemblies. Thebasic mattress 104, or “patient surface,” of the bed consists of aspecialty low air loss mattress providing a comprehensive system ofpulmonary and skin care therapies for the critically ill, immobilizedpatient 118. Such therapies include gentle side-to-side rotation of apatient, percussion (or vibration) therapy, and gentle pulsation of theair cells supporting the patient. The system further comprises anautomated CPR mode, which is—activated and deactivated via a pluralityof CPR mode activation controls. The detailed operation of the CPR modeactivation system will be apparent further herein.

Frame assemblies 103 and accompanying patient surfaces 105 providesupport for the patient's head and back, buttocks, and legs and feet. Aprovided head and X-ray assembly 103 a further comprises a mechanism forholding an X-ray cassette, detailed further herein. A provided seatassembly 103 b further comprises a set of jack motors used to adjust theangular orientation relative to seat assembly 103 b of head and X-rayassembly 103 a and leg assembly 103 c, as will be evident furtherherein. A provided foot board assembly 115 is dependently attached tothe leg assembly 103 c by means providing useful benefit to both thepatient 118 and caregiver, also detailed further herein.

The base frame 101 generally comprises longitudinal beams and transverseelements. The base frame 101 further comprises a plurality offloor-engaging casters 106, conventionally journaled near the fourcorners of said frame. Locking mechanisms 114 are provided for thecasters 106. Such locking mechanisms 114 may be set to prevent eitherrotation or steering of the casters 106, hence holding bed 100stationary, as is conventional with many hospital bed frames. Weldmentsare provided which allow location of corner posts 108 on which may beinstalled intravenous injection (IV) holders or standard tractionframes. The corner posts 108 are adapted with convenient integral handholds to facilitate patient entrance or exit of the bed 100. The handholds, as provided by the comer posts may also assist caregivers intransport of the bed 100. The bed's controls are contained in a 360degree swivel mounted on either foot comer post 108 a, 108 b. The swivelallows the controller 117 to be moved out of harm's way during transportthrough doors and hallways. Because the swivel provides flexibility inlocation and orientation of the controls, the need for multiple controlpanels is eliminated. Elimination of multiple control panels eliminatescomplicated wiring schemes and reduces overall failure modes.

Molded plastic covers 109 enhance aesthetic appeal and provideconvenient locations for affixing instructions 129 or warning labels.Bumpers made of rubber or other similar materials may also be installedon covers 109 for protection of both bed and the walls and doorways ofthe facility where the bed 100 is used.

The load frame 102 generally comprises longitudinally disposed beams andtransverse elements. Additional transverse elements are used forattachment of jack motors. The description and function of such motorswill be apparent further herein. The load frame 102 is referred to assuch, because it carries the entire load of the patient surface. Itdependently attaches to the base frame 101 in a way that weighs thatload as it is transmitted to the base frame 101. That connection betweenthe load frame 102 and the base frame 101 is provided by a scalemechanism well known in the art and similar to that described in U.S.Pat. No. 4,793,428, incorporated herein by this reference as though nowset forth in its entirety. The scale mechanism generally comprises apair of displacement transmitting members, which are respectivelyconnected between transverse elements via flexures.

Each transmitting member is attached to a base frame element via aflexure and also to a load frame element via a flexure. Attachment inthis manner causes displacement of bars which are connected to themembers in a cantilevered manner. Displacement, which is limited bysprings, is measured in the area of the springs by linear variabledifferential transformers (LVDTs). Displacement measured by the LVDTscorresponds in direct proportion to the weight of the load frame and allwhich is supported thereby. A locking mechanism comprising commonhardware is desired to prevent motion of the load frame 102 relative tothe base frame 101 during transport of bed 100. This serves to preventdamage of the scale mechanism due to excessive forces as may beencountered when attempting to negotiate a short step or the like. Otherconventional mechanical stops are used to limit movement and preventdamage in normal use, when the locking mechanism is not utilized.

A raise-and-lower mechanism produces vertical movement and Trendelenburgtilting of the seat assembly 103 b. In particular, a head torque armweldment and a foot torque arm weldment are pivotally attached to theload frame 102. The seat assembly 103 b is dependently attached toweldments by members. Specifically, the foot torque arm weldmentconnects at points to members by bushings and other necessary hardwareas is well known in the art of manufacturing hospital beds. The headtorque arm and foot torque arm weldments are articulated about theirpivotal attachments to the load frame by extension or retraction of jacktubes (or “sleeves”) by jack motors. The jack motors, of the typereferred to in the industry as linear actuators, attach the transversemembers of the load, frame by torque arm pins, themselves affixed bycotter pins.

Extension of either tube by the corresponding motor causes the attachedweldment to pivot relative to the load frame 102 such that theconnection points of the corresponding members articulate upwardly.Retraction of either tube would have the opposite effect, that oflowering the members. Said articulation has the effect of causing themembers to raise or lower in vertical motion, thereby raising orlowering seat assembly 103 b in vertical motion. In the preferredembodiment, such articulation as raises seat assembly 103 b is said toprovide a BED UP function. Such articulation as lowers seat assembly 103b is said to provide a BED DOWN function. It is believed that the systemdescribed herein, having mechanically articulated attachment points atthe four comers of the seat assembly 103 b, promotes greater stabilitythan would a system utilizing hydraulic type cylinders wherein thesupport is typically concentrated along a single longitudinal axis.

Articulation by one jack motor greater or less than that of the otherjack motor has the effect of establishing the patient support surface105 in a Trendelenburg or reverse Trendelenburg treatment position.Trendelenburg and reverse Trendelenburg therapy is well know in the artfor treatment of certain cardiac conditions and is considered animportant feature for many conventional hospital beds, although theexcessive weight of bariatric patients has led the art away fromincorporating such features in a bariatric bed. The preferred embodiment100 is capable of achieving ten degrees Trendelenburg or twelve and onehalf degrees reverse Trendelenburg therapy. Articulation to effect suchtreatment is referred to as providing the TRENDELENBURG. or REVERSETRENDELENBURG function.

The head assembly 103 a is dependently attached to the seat assembly 103b by laterally oriented hinging. Articulation of the head and X-rayassembly 103 a about this hinge is effected by extension or retractionof a jack sleeve under the force of a jack motor. The jack motor, of thetype referred to in the industry as a linear actuator, dependentlyattaches to the seat assembly weldment by a pin, itself affixed by acotter pin. The jack sleeve attaches to the head and X-ray assemblyweldment by a pin, itself affixed by a cotter pin. In the preferredembodiment, extension of the jack sleeve is said to provide a HEAD UPfunction. Retraction of the jack sleeve is said to provide a HEAD DOWNfunction. The head assembly 103 a for the treatment system generallycomprises a rail encompassing a head board. The rail and head board aremated together with weldments. The weldments provide a channel forhorizontal containment of an X-ray cassette. The transverse weldmentcombines with a hinge and another weldment to provide structural supportof the head and X-ray assembly. An X-ray board serves to maintain theright-angled shape of the perimetrical structure, thereby facilitatingease of insertion and removal of an X-ray cassette. The X-ray board andhead board of the preferred embodiment comprise a radiolucent material.While it is well known in the art of design and manufacture of patienttreatment beds to provide a mechanism for holding an X-ray cassettebehind the patient's head and chest areas, prior art designs have notimproved the means for insertion and removal of the X-ray cassette.Specifically it is desirable to be able to raise or lower the cassettefrom one side only so that in cases where access to the treatment bedmay be limited to one side, by a wall or medical apparatus, forinstance, an X-ray cassette still may be easily inserted andsubsequently removed. Because prior art embodiments of bariatric beds donot provide mechanisms for keeping the sides of an X-ray cassetteparallel with the sides of the holding assembly, the caregiver has beenforced to have access to both sides of the treatment bed in order tomanually guide the cassette into place. The embodiment 100 detailedherein utilizes a mechanism from other arts to provide a solution to theproblem described. A block and pulley system, comprising a left blockand right block, plurality of single pulleys, plurality of doublepulleys and plurality of cables, allows the X-ray bar to be raised andlowered from just one of a plurality of handles, although nothingprevents two or more handles from being used, all the while maintainingthe bar in a position parallel to the transverse element. The handlesmay lock at a plurality of vertical positions within slots in thechannel members. Although referring to an unrelated field of art, theblock and pulley system shown is similar to that described in U.S. Pat.No. 5,295,430, incorporated herein by this reference as though here nowset forth in its entirety.

The leg assembly 103 c is dependently attached to the seat assembly 103b by a laterally oriented hinge. Articulation of the leg assembly 103 cabout this hinge is effected by extension or retraction of a jack sleeveunder the force of a jack motor, of the type referred to in the industryas a linear actuator, which dependently attaches to the seat assembly,weldment by a pin, itself affixed by a cotter pin. The jack sleeveattaches to the leg assembly weldment by a pin, itself affixed by acotter pin. In the preferred embodiment, extension of the jack sleeve issaid to provide a LEGS UP function. Retraction of the jack sleeve issaid to provide a LEGS DOWN function. The leg assembly is detailedfurther herein with discussion of the foot board assembly.

In the preferred embodiment, full extension of the head jack sleeve inorder to provide full HEAD UP and simultaneous full retraction of thelegs jack sleeve in order to provide full LEGS DOWN causes conversion ofthe bariatric treatment system bed into a bariatric treatment systemreclining chair, as depicted by FIG. 5. In combination with uniquebenefits provided by the leg and foot board assemblies, as well as bythe therapeutic mattress system, detailed further herein, the chairposition of the bariatric treatment system is particularly suited towardfacilitation of entrance or exit of the bed by a bariatric patient. Itshould also be noted that the seat assembly provides a convenientmounting location for patient restraint system weldments, as are knownby those of ordinary skill in the art and may or may not be desireddepending upon the specific application.

The foot board assembly 115 is dependently attached to the leg assembly103 c. The leg assembly 103 c generally comprises a leg plate asreinforced by an “I” shaped weldment. This weldment comprises aplurality of attachment points, the purpose of which will be evidentherein. The foot board assembly generally comprises a foot plate aplurality of hinges, cushions and a heavy duty fabric cover. The cover,in the preferred embodiment, is “Dartex P 109,” commercially availablefrom Penn-Nyla of Nottingham, England.

In the preferred embodiment of the present invention 100, the foam usedfor the foot plate lower cushion is a antimicrobial open-cellpolyurethane foam having a relatively large density of 2.7 pounds percubic foot and 70 pounds compression. The foam used for the foot plateupper cushion is a similar antimicrobial open-cell polyurethane, but isless dense than the lower cushion, having a density of 2.0 pounds percubic foot and 41 pounds compression. Both cushions are wedge-shaped,with their greater thicknesses (roughly 1.75 inches and 0.5 inch,respectively) being distal to the hinge. The relative characteristics ofthese foam cushions serve their varied purposes.

It is well know in the art of designing and manufacturing bariatricpatient treatment beds to provide a means by which the patient caneasily enter or exit the bed. The patient foot board assembly 115 nowdescribed, including the unique dampening features briefly described inthe following, is identical to that fully enabled in U.S. patentapplication Ser. No. 08/382,150, filed Jan. 31, 1995, hereinaboveincorporated by reference. Bariatric patients are often not able to hopor step down even short distances without injury or loss of balance. Itis therefore desirable to provide a means for entrance or exit whichlifts the patient into the bed and similarly sets the patient's feetvery near the floor when exiting the bed. In the prior art, it has beenshown that a rigid foot board in combination w7th a chair positionfeature, as previously detailed herein, facilitates bariatric patientcare. However, measures are taken to ensure such foot boards are notused as a step when exiting the bed, presumably for safety reasons inview of the excessive weight of bariatric patients. The presentinvention goes against such teachings by providing a foot board which isadapted to be used safely as a step for bariatric patients.

The foot board assembly 115 attaches to the leg assembly 103 c by suchmeans as to provide gradual increase in rigidity as weight is applied tothe foot cushion 116, so as to provide adequate support of the bariatricpatient entering or exiting bed yet avoiding fixed resistance to asudden increase in force. The primary attachment of the foot boardassembly to the leg assembly is by a hinge through weldments on the footboard assembly and a plurality of holes in a weldment of the legassembly. Articulation about this hinge is constrained by dampeningcylinders and a spring, as detailed further herein. The spring, incompression, attaches to the leg assembly weldment by a pin, itselfaffixed by a cotter pin. The spring attaches to the foot board assemblyweldment also by a pin, itself affixed by another cotter pin. Ahydraulic cylinder, of the type which dampens primarily in compression,attaches to the leg assembly weldment by a pin, itself affixed by acotter pin. The compression hydraulic cylinder attaches to the footboard assembly weldment also by a pin, itself affixed by another cotterpin. A hydraulic cylinder, of the type which dampens primarily intension, attaches to the leg assembly weldment by a pin, itself affixedby cotter pin. The tension hydraulic cylinder attaches to the foot boardassembly weldment also by a pin, itself affixed by another cotter pin.The particular cylinder selected for compression dampening is, in thepreferred embodiment of the present invention, an adjustable cylinderhaving a two-inch stroke and available through Enidine of Orchard Park,N.Y., part number (LR)OEM 1.SM X 2. The particular cylinder selected fortension dampening is, in the preferred embodiment of the presentinvention, an adjustable cylinder having a four-inch stroke and alsoavailable through Enidine of Orchard Park, N.Y., part number ADA S 1 OT.The particular spring selected is, in the preferred embodiment of thepresent invention, a medium load, round wire spring available throughLee Spring Company of Brooklyn, N.Y., part number LHL-1 SOOA-9MW.

Under the weight of a bariatric patient, the compression dampeninghydraulic cylinder increasingly resists articulation of the foot boardassembly about the attaching hinge. Gradually, resistance will increaseas more weight is applied by the patient. In this manner, the foot boardassembly is able to provide increasingly rigid support of the bariatricpatient while minimizing any risk of snapping under the weight of atypical bariatric patient. Further, if a bariatric patient should applyweight onto foot board at excessive speed, the dampening action of thecompression dampening hydraulic cylinder may serve to prevent injury tothe patient's knees and legs. Once weight is removed from foot board(such as once the patient has completely exited the bed), the springreturns the foot board assembly to its original position with respect tothe leg assembly. The tension dampening hydraulic cylinder resists thereturn motion of the spring. Such dampening helps prevent snapback ofthe foot board assembly, which might otherwise present safety hazards.

The cushions not only enhance patient comfort but can also cushionengagement of the foot board with the floor as the patient exits orenters the bed. Additionally, in case a caregiver is unalert and placesa foot beneath foot board assembly, and a patient's weight does causethe foot board assembly to contact the caregiver's foot, heavy paddingof the lower cushion distributes the weight and cushions the caregiver'sfoot to help prevent excessive discomfort or physical injury.

Pins 134, held in position beneath the foot board assembly by nuts, maybe placed in a release position so as to allow the foot plate toarticulate about a secondary attachment hinge. Said release allows thepatient support foot cushion to lie coplanar with the leg cushion. Thismay be desirable when the bed surface is in a horizontal position andthe caregiver wishes to minimize pressure against the patient's feet.

The left side rail 110 a generally comprises a metal frame encased bymolded plastic covers 111 a The frame is generally dependently attachedto a side rail mounting plate through weldments and shafts,substantially identical those fully enabled in U.S. patent applicationSer. No. 08/382,150, filed Jan. 31, 1995, hereinabove incorporated byreference. These weldments and shafts are themselves major components ofa mechanism for raising and lowering of the side rail assembly. Saidmechanism is also utilized for lateral translation of the side railassembly, thereby extending or compressing the lateral dimension of thebariatric treatment system. Details of the manufacture and use of thismechanism will be evident further herein.

The aforementioned mechanism comprises those elements necessary forraising, lowering or laterally translating the left side rail. Weldmentsare dependently cantilevered, in fixed relation from shafts. The shaftsfreely rotate and slide laterally within bushings. These bushings aredependently attached to a mounting plate in fixed position. Pawls areconnected by a rod in such manner as to require coordinated motion ofsaid pawls. A plurality of rectangular pegs form teeth on the shafts insuch a manner as to form a ratchet mechanism with the pawls. In thepreferred embodiment of the present invention, the ratchet mechanismallows the side rail to be raised by lifting only from a lowestTRANSPORT position to either a middle LOWERED position or the upperRAISED position. In order to lower the side rail from the RAISEDposition to the LOWERED position or from the LOWERED position to theTRANSPORT position, a provided release lever must be manuallyarticulated in order to cause release of the pawls from the teeth of theshafts. From the LOWERED position, the side rail may be freelytranslated laterally outward from the center of the bed. Thisconfiguration is referred to as EXTENDED in the preferred embodiment.From the EXTENDED position, the side rail may be returned to the RAISEDposition. The side rail, when in the EXTENDED RAISED position, must belowered prior to translation back toward the center of bed, the NORMALposition. In the TRANSPORT position, the side rail of the preferredembodiment may be further translated toward the center of the bed, to alocation beneath the seat assembly, thereby maximally reducing theoverall lateral dimension of the bed. The reduction in lateral widthattainable is sufficient so as to be able to fit the bed through astandard hospital doorway. Although the excessive width of bariatricpatient treatment beds has long been recognized as an undesirablecharacteristic for transport, prior art embodiments of bariatric patienttreatment beds have failed to provide an economical, reliable andeasy-to-manufacture side rail design with multiple functions andabilities for use on a bariatric bed such as that described herein.

As is well known in the art, the bariatric patient 118 is often of suchlimited mobility as to make it impracticable for such a patient toutilize bed function controls mounted on a side rail. The preferredembodiment of the present invention includes a hand held bed functioncontrol pendant 124 which comprises a molded plastic body encompassingnecessary electronic hardware, as is common in the industry, and a clip125 for easy stowage upon a side rail 110. The pendant 124 includes aplurality of push button membrane switches allowing the patient 118 tocontrol such functions as BED UP, BED DOWN, HEAD UP, HEAD DOWN, LEGS UPand LEGS DOWN, as have been previously detailed. The pendant 124attaches to the swivel mounted main control 117 panel by a cord 126 andplug. An infrared hand held control 127 is also provided in thepreferred embodiment. The infrared control 127 comprises the samefunctionality as does the hardwired pendant 124 and also comprises asimilar attachment clip 128. It communicates with the master controllerthrough an infrared detector, and associated hardware and software,mounted on the underside of the swivel mounted main control panel 117.As will be understood further herein, a serial bus architecture,employed extensively in the preferred embodiment of the presentinvention, allows simple, parallel implementation of the three controlunits 117,124,127.

The therapeutic structure of the bariatric treatment system 100generally comprises a patient support surface, blower and valve boxassemblies, and a patient rotation angle sensing system. The patientsupport surface 105, normally covered by a sheet, generally comprises aplurality of patient support air cushions 130-133, turning air bladders135, patient restraining bladders 136 and a percussor bladder. All airbladders in the preferred embodiment comprise a polyurethane coated,impermeable, heavy duty fabric.

The patient support air cushions 130-133 are inflated by air which hasbeen transmitted through a plurality of polyethylene hoses from a blowerand valve assembly 137. The plurality of hoses are connected to thecushions sectionally, hence compartmienting air flow into the headsection 130, back section 131, torso section 132 and legs section 133.Further, the cushions of the back 131, torso 132 and legs 133 sectionsare supplied with air from the hoses in alternating fashion. This allowsthe patient 118 supported upon the surface to receive pulsation therapyas is well known in the treatment and prevention of bedsores, ordecubitus ulcers, and other pressure related complications of extendedconfinement to hospital beds. Pulsation therapy is accomplished by firstreducing pressures through the hoses feeding every other bladder in thedesired pulsation region, hence deflating the attached cushions. Uponattaining the maximum desired deflation in these cushions air flow isrestored through the hoses, again inflating the connected cushions.Simultaneously, with the re-inflation of the first deflated cushions,pressure is decreased in each bladder adjacent those being reinflated,within the pulsation region, by decreasing flow through the hosesconnected thereto. Upon attaining the maximum desired deflation in thissecond group of bladders, and simultaneously the maximum desiredinflation in the first group of bladders; the cycle is reversed andrepeated. It should be noted that for the purpose of this discussionmaximum desired inflation and deflation is determined by the desiredtherapy intensity which in the preferred embodiment is caregiverselectable as LOW, MEDIUM or HIGH PULSATION. Under the control of themicroprocessor systems detailed further herein, this pulsation isavailable with cycle periods from two to forty minutes. Separation ofthe air cushions of the back section 131, torso section 132 and legssection 133 also allows independent adjustment of maximum pressures ineach region thus allowing more optimal minimization of pressure pointsagainst the patient. The cushions 130 of the head section are suppliedwith air taken from splices 138 into the those hoses which supply air tothe back section. The air is first fed into a shuttle and check valvesystem 139, wherein any pulsation which may be activated is dampenedout. In particular, a shuttle valve 140 acts to pass the highestpressure air from either of the two lines to a restricted flow port 141.A check valve 142 is provided which allows air flowing to the headsection 130 to only pass through the flow port 141. In the event thatCPR functions are activated, as will be understood further herein, thecheck valve 142 allows flow from the head section 130 to pass throughthe flow port 141 as well as through a much larger port about the checkvalve 142. The restricted, or dampened, air flow is then directed intothe cushions 130 of the head section which exhibit only minimalpulsation effects.

The patient restraint bladders 136 are also inflated throughpolyethylene hoses which originate from the same blower and valveassembly 137 as do the hoses to the patient support cushions 130-133. Inparticular, these bladders 136 are inflated from a hose spliced into oneset of hoses feeding the torso section 132. A check valve 143 isprovided which prevents the restraint bladders 136 from deflating withpulsation therapy. A plurality of bladders 119 is provided for expandedpatient support when the bariatric treatment system 100 is in theEXTENDED side rail position, as described hereinabove. The bladders 119receive inflating air through hoses spliced into the set of hosesfeeding the torso section 132 not spliced to the restraint bladders 136.A check valve 144 such as that utilized for the restraint bladders 136is provided to prevent deflation of the expanded support bladders 119during pulsation therapy in the torso section 132. When the EXTENDEDposition is not selected, these bladders are disconnected from theirsupply hoses and tucked away beneath the back 105 b and legs 105 csections of the patient support system 104. A manual three way valve 14is provided to prevent uncontained discharge of air during the conditionwhere these hoses are disconnected. Except for the modifications asnoted hereinabove, the construction and operation of the foregoinginflation structure 146 is substantially identical that disclosed inU.S. patent application Ser. No. 08/672,442, filed Jun. 28, 1996,hereinabove incorporated by reference.

The inflation structure 146 for the turning bladders 135 generallyprovides for a LEFT ROTATION and a RIGHT ROTATION turn of the patient. Aleft rotation turn of the patient accomplished by inflation of the leftturning bladder 135 a through a first hose from the valve block 137while simultaneously exhausting air in the right rotation bladder 135 bthrough a second hose from the valve block 137. Similarly, a rightrotation turn of the supported patient 118 is accomplished by inflationof the right turning bladder 135 b through the second hose whilesimultaneously exhausting air in the left turning bladder 135 a throughthe first hose.

The best mode embodiment of the bariatric treatment system's valve blockassembly 137 generally comprises a manifold 147 with a motor mountingplate 148 supported a distance separated from the manifold by aplurality of industry standard stand-offs. Dependently mounted upon themotor mounting plate is a plurality of 12-volt, reversible direction,direct current motors 149. Each such motor 149 is provided withelectrical connection from a positive terminal 150 and a negativeterminal 151 through a connector to a relay board, understood furtherherein. Each motor 149 is further provided with a chassis groundconnection 152. Additionally, the valve block assembly 137 comprises aplurality of air tubes 153 which provide air flow to the patientsupporting air cushions 130-133, extension and restraint bladders 119,136, and turning bladders 135 as hereinabove described.

Each valve control motor 149 further comprises a valve control motorshaft 154 connected to a coupling 155 by a pin 156, which coupling 155further connects to a valve screw 158 by another pin 157. In thepreferred embodiment 100 space is conserved by utilizing a valve screw158 which is of adequate diameter to fit coaxially over the coupling155, hence eliminating the need for an additional shaft. This reducesthe longitudinal dimension of the valve block assembly 137 whileutilizing only that space otherwise required due to the diameter of thevalve motors 149. Connection of each shaft 154 to its correspondingvalve screw 158 via a coupling 155 and pins 156, 157 allows floating ofthe valve screw 158, promoting self-alignment with the valve spool 159.This design simplifies manufacture and increases reliability of thevalve block assembly's operation.

U.S. patent application Ser. No. 08/672,442, filed Jun. 28, 1996,hereinabove incorporated by reference, shows a valve motor with a valvespool in the air inflation position, no flow position and air exhaustingpositions, respectively. When the valve motor turns in the valve openingdirection, the valve screw drives the valve spool away from the valvemotor creating a flow path between an internal cavity and thecorresponding hose connection tube. The cavity is pressurized by ablower within a provided blower and valve block housing. In an alternateembodiment, without loss of performance, this blower may be mountedseparately from the housing and cavity. In such an embodiment, which maybe advantageous for conservation of space, the blower would connect tothe cavity via an air hose. Air flow between the cavity and tube servesto inflate any air bladders which may be connected. The applicationshows the valve spool in the closed position so as to block any flowinto or out of the corresponding tube. The application also shows thevalve spool in the exhausting position. When the valve motor turns inthe valve exhausting direction, the valve screw drives the valve spooltoward the valve motor creating a flow path between the correspondingtube and the atmosphere. In the exhausting position, air escapes to theatmosphere from whichever bladders may be connected to the tube. Flow tothe atmosphere takes place between the manifold and motor mountingplate. Because of the ability to provide control of three way air flowsas described, embodiments making use of spool valves are preferred overembodiments which attempt to make use of poppet valves, or other formsof valves which rise perpendicularly to or from their seats. Use of “V”shaped slots in the valve spool bore allows fine control of air flow dueto the gradual opening of the air port which is provided by such slots.

In the preferred embodiment, the cavity of the valve block assembly ismodified to allow insertion of a nylon thumb screw in order to limit theopening motion of the valve spools under control of the two valve motorsutilized to control air flow into and out of the turning bladders. Thethumb screw maintains the valve spool position within the region ofcontrol of air flow. Such maintenance of the region of control isnecessary for the efficient operation of the rotation function, controlalgorithm, detailed further herein. The construction and operation ofthe valve block assembly 127, as hereinabove summarized, issubstantially identical that fully enabled in U.S. patent applicationSer. No. 08/672,442, filed Jun. 28, 1996, hereinabove incorporated byreference.

The percussor system 160 of the bariatric treatment system 100 generallyincludes a blower 161, a valve block 162 (also referred to as a“percussion body”) and a solenoid 163. The blower 161 is powered by aninternal three speed alternating current motor. Said motor 161 iscontrolled by an internal circuit board in response to inputs receivedthrough direct current channels through a transmission line assembly.The three speeds of the blower allow for three levels of intensity forpercussion therapy, LOW, MEDIUM and HIGH PERCUSSION, as will be evidentfurther herein.

The percussor valve block 162 generally comprises a longitudinallyarticulable rod 164 upon which are mounted first 165 and second valvedisks 166. The position of the rod 164 determines the air flow paththrough the valve block 162 at any given instance. There are generallytwo conditions. In the first condition, the rod 164 is biased, by aprovided wire spring 167, distally from a provided solenoid 163. In thisposition, the first disk 165 is held away from its seat 168 and thesecond disk 166 mates with its seat 169, allowing airflow into thepercussor valve block 162 to exhaust partially to the atmosphere andpartially to the percussor bladder. In the second condition, thesolenoid 163 pulls the rod 164 toward itself, thus causing the firstdisk to mate with its seat and the second disk to be removed from itsseat. In this condition, airflow into the valve block from the blower isfully exhausted to the atmosphere. Further airflow form the percussionbladder is also allowed to exhaust to the atmosphere.

The blower 161 operates continuously at a given speed, depending uponthe intensity of percussion desired. By splitting the airflow whileinflating the percussion bladder, the blower is prevented from enteringa dead-head condition in which flow is stalled. This ensures maximumintensity of percussion action as well as prevents overheating of theblower at lower percussion frequencies.

The therapeutic structure of the bed further comprises a hinging systemwherein a plurality of straps, comprising heavy duty webbing, arearranged in a criss-cross fashion along the longitudinal axis of thepatient support sub-frame. This hinging system is exactly like thatdisclosed in U.S. patent application Ser. No. 08/672,442, filed Jun. 28,1996, hereinabove incorporated by reference.

The turning bladders 135 utilized in the presently preferred embodimentof this invention 100 are substantially similar those of U.S. patentapplication Ser. No. 08/672,442, filed Jun. 28, 1996, hereinaboveincorporated by reference, except that only two are provided and theseare modified for maximum turning efficiency under a bariatric patient.In particular, internal baffles are provided which maintain the bladdercross section in a right triangular shape with a smaller angle much lessthan the greater angle. In this manner, the bladder is prevented fromassuming a cylindrical shape and thereby places maximum area (that ofthe hypotenuse panel) in contact with the underside of the patientsupport surface. The zippering and other features described inapplication Ser. No. 08/672,442 remain as disclosed.

The patient rotation angle sensing system is identical that disclosed inU.S. patent application Ser. No. 08/672,442, filed Jun. 28, 1996,hereinabove incorporated by reference. The angle sensor thereindescribed is further utilized in two additional places in this presentinvention. Angle sensors 113 are placed on the articulating membersconnecting the load frame to the mid-frame. System software performstrigonometric calculations upon the measured angle data in order toaccurately estimate the exact patient orientation. This informationallows the bariatric treatment system to assume a number of givenpositions, such as TRENDELENBURG and others, automatically at the pressof a control panel button.

A power inverter, rechargeable batteries, circuit breaker, relay andconnecting brackets and the like are maintained in the lower frameassembly. Such components provide the bariatric treatment system withstandard AC power supply and, alternately, an AC-like power supply fromthe rechargeable batteries. The power system is identical to thatdisclosed in U.S. patent application Ser. No. 08/672,442, filed Jun. 28,1996, hereinabove incorporated by reference.

Functional control of bed and therapeutic features is provided throughan integrated hardware and software implementation 170. In general, thefunctional aspects of the bariatric treatment system 100 may besummarily described as comprising a master board and display system 171with infrared receiver board 172, a communications logic board 173, asensor board 175, a relay board 176, a percussor board 174, a scaleboard, an infrared transmitter system 179, and a power supply andbattery backup system 178, all in operable communication with aplurality of jack motors and the therapeutic patient treatment systemalong with various pressure sensors, angle sensors, infrared sensors andlimit switches, integral therewith.

The master board 171 of the preferred embodiment of the presentinvention 100, implemented on a four layer printed circuit board (PCB)with power and ground planes, is designed about a trademark “INTEL”device number 80C32 microcontroller, commercially available from theIntel Corporation of Santa Clara, Calif. The master board is powered bya direct current to direct current (DC-DC) converter which converts 12volt direct current (Vdc) power from the bariatric treatment systempower supply to 5-Vdc power, which is regulated by a provided 5-Vdcregulator. The DC-DC converter ensures the presence of sufficient powerat the master board in order to prevent voltage sags incident varyingdemand in the general power distribution scheme. The 80C32microcontroller operates at a clock rate of 11.0592 mega-Hertz (MHz), asprovided by an on-board crystal oscillator circuit. As is understood bythose of ordinary skill in the art, clocking at 11.0592 MHz allowsgeneration of industry standard baud rates, utilized throughout thebariatric treatment system for serial communications between the variousprovided integrated hardware and software control circuits. The 80C32includes an integral universal asynchronous receiver and transmitter(DART) for serial communications with peripheral boards, as will beunderstood further herein.

The master board also includes a WaferScale Integration (WSI) devicenumber PSD313 programmable microcontroller peripheral with erasablememory, commercially available from WaferScale Integration, Inc. ofFremont, California, which comprises a 128 kilobyte (Kbyte) ultravioleterasable programmable read only memory (UV EPROM), of which 64 Kbytesare utilized by the 80C32 for program storage, and a 2 Kbyte staticrandom access memory (SRAM), utilized by the 80C32 for storage ofsoftware control variables. The PSD313 also provides programmablearrays, utilized by the master board software for memory mapping andcreation of data input and output (I/O) ports.

The master board includes a trademark “BENCHMARQ” device numberbg3287EMT real-time clock (RTC) module, commercially available fromBenchmarq Microelectronics, Inc. of Carrollton, Tex. The bq3287EMT isutilized by the 80C32 for error logging and time and date stamping ofpatient weight information, each understood further herein. Thebq3287EMT also provides 242 bytes of non-volatile SRAM, utilized by the80C32 for storage of system parameters and diagnostic error logs.

A trademark “DALLAS SEMICONDUCTOR” device number DS 1232 micromonitorchip, commercially available from the Dallas Semiconductor Corporationof Dallas, Tex., is utilized by the 80C32 as a watchdog timer, as isunderstood by those of ordinary skill in the art. The DS1232 provides ahard reset to the 80C32 in the event of a software failure, as will beunderstood further herein.

The display system of the bariatric treatment system generally comprisesa plurality of membrane switches and a vacuum fluorescent display (VFD),commercially available from Futaba of, configured for six lines of 40characters per line. Interface from the master board to the membraneswitches is directly provided for by external data ports of the 80C32.The membrane switches are electrically arranged in a matrix. Depressionof any single membrane switch shorts one row to one column. The 80C32successively writes to each row of membrane switches while rapidlyreading each column of membrane switches. In this manner, the 80C32determines whether any row and column is shorted together, therebyindicating depression of a particular membrane switch. Interface fromthe master board to the VFD is provided by a trademark “MOTOROLA” devicenumber M68HC11 single-chip microcontroller, commercially available fromMotorola, Incorporated's Motorola Semiconductor Products Sector ofPhoenix, Ariz., The M68HC 11 formats display driver data from the 80C32and then passes the formatted data to the VFD through a 34 pin flatribbon connector.

Two distinct serial communications busses are supported by the masterboard. A trademark “NATIONAL SEMICONDUCTOR” device number DS36276FAILSAFE multipoint transceiver, commercially available from theNational Semiconductor Corp. of Santa Clara, Calif., is utilized on themaster board to implement a six-wire RS-485 bus. Those of ordinary skillin the art will recognize that the RS-485 bus is the recommendedstandard of the Electronic Industries Association (EIA) for specifyingthe electrical characteristics of generators and receivers used inbalanced digital multipoint systems. The RS-485 standard is alsosometimes referred to as the EIA485 standard, without loss of meaning. Asecond bus of eight wires, proprietary to Kinetic Concepts, Inc. (KCI)of San Antonio, Tex. and referred to as a KCI bus, is provided fordirect interface to any peripheral board not implementing the RS485standard. A discretely, implemented low power, dual metal oxidesemiconductor field effect transistor (MOSFET) driver circuit providesinterface from the master board to the KCI bus. As will be understoodfurther herein, and particularly after discussion of the communicationslogic board, communications signals on the RS485 bus and the KCI bus arelogically mirrored such that all signals appearing on one bus aresimultaneously transmitted on the other. Signals from the master boardare simultaneously transmitted by direct electrical connection to bothbusses. Signals to the master board, which are logically identical,arrive either from the RS485 bus or from the KCI bus, according to theplacement of a jumper switch on the master board. Irrespective of whichbus is utilized, all serial communications to or from the master boardare through the communications logic board as will be more fullyunderstood herein. Electrical interface between the master board and thecommunications logic board is provided for through a six-pin modularconnector to the RS-485 bus and an eight-pin modular connector to theKCI bus.

The master board extensively utilizes memory mapping—a listing of allthe memory assignments as implemented in the program software,categorized as either program space or data space. Memory mapping allowsthe 80C32 to identify the amount of memory required, the locations ofdata or subroutines, and those memory locations not allocated orutilized. In the preferred embodiment of the present invention, thememory mapping allocates 64 Kbytes as program space and 64 Kbytes asdata space which also includes I/O port allocations. The 80C32 readssystem program instructions from the program space and, as required,reads from and writes to the various peripheral devices, as isunderstood by those of ordinary skill in the art, in order to effect orutilize system parameters, error logs, membrane switch I/O, VFD driverdata and software control variables. The provided memory mapping issummarized in Table 1: Master Board Memory Mapping. This table specifieswhether the 80C32 reads (R), writes (W) or reads and writes (R/W)particularly addressed, as delineated in hex (Address Range), systemprogram instructions (PROG) or data and I/O (DATA) out of or into thespace (Space) allocated to a particular device (Device). The table alsoincludes an abbreviated summary of the function (Function) implementedunder each assignment. TABLE 1 Master Board Memory Mapping R/W AddressRange Space Device Function R 0-xFFFFh PROG PSD313 Program instructionR/W 0-x1FFh DATA bq3287EMT System parameters/error logs R/W x200h-x3FFhDATA Ext. Data Ports Membrane switch I/O W x400h-xSFFh DATA M68HC11 VFDdriver data R/W x2000h-x27FFh DATA PSD313 Software control variables Rx4000h-xFFFFh DATA PSD313 Reserved

A detailed schematic drawing of the master board 171 is provided atFIGS. 16A, 16B, 16C, and 16D. This detailed schematic is enabling, tothose of ordinary skill in the art, of the above-recited structure andfunction.

The communications logic board 173 may be summarily described as thecentral node of a star architecture implementation of the dualcommunications bus structure (RS485 and KCI) of the preferred embodimentof the present invention. This implementation is effected throughprovision of six six-pin modular connectors for RS-485 bus connectivity,six eight-pin modular connectors for KCI bus connectivity, and one DB-9connector and three four-pin modular connectors for RS-232 serialcommunication line connectivity. Those of ordinary skill in the art willrecognize that RS-232 is the EIA recommended standard for single-endeddata transmission, that is data transmission using only one signal, atrelatively low data rates (up to 20 kilo-bits per second (Kbps)) overshort distances (typically up to ˜50 feet). As will be furtherunderstood herein, the board, implemented on two four layer PCBs eachhaving power and ground planes, creates a logical mirror between theRS-485 bus and the KCI bus and between these busses and two providedRS-232 serial communications jacks. The two PCBs of the communicationslogic board, electrically interconnected through a 32 wire flat ribboncable, may be stacked or placed side-by-side according to the physicalconstraints of the particular embodiment in which they are implemented.An LM294OCT-5 linear voltage regulator supplies regulated 5-Vdc power tothe communications logic board.

The communications logic board of the preferred embodiment of thepresent invention, is designed about a trademark “ALTERA” device numberEPM7032 programmable logic device (PLD), commercially available from theAltera Corporation of San Jose, Calif. The EPM7032 operates at a clockrate of 3.6864 MHz, as provided by an on-board crystal oscillatorcircuit. As is understood by those of ordinary skill in the art,clocking at 3.6864 MHz is compatible with implementations of industrystandard baud rates as are utilized throughout the bariatric treatmentsystem. The EPM7032 is custom designed to create a logical mirrorbetween the RS-485 bus, the KCI bus, and the RS-232 serialcommunications lines. As will be understood herein, appropriate driverand buffer circuitry is provided whereby all electrical communicationsto or from the various serial communications busses and lines areprovided within transistor transistor logic (TTL) electrical standards.In order to prevent latching and collision, the three inputs to theEMP7032 are successively sampled at the 3.6846 MHz clock rate throughlatching of the EMP7032's internal gates. Upon detection of a signal onany of the three input lines, the EMP7032 is programmed to (1) disablesampling of the next two input lines, thus preventing collision, and (2)disable the output of the sampled input and disable the inputs of thetwo non-sampled outputs thus preventing latching of the outputs. On thenext clock cycle, the sampled input data is transmitted on the outputsof the two non-sampled lines. This process is very rapid, the only delaybeing one clock cycle and propagation time. Because the EMP7032 isclocked at a much higher rate than the maximum data transmission rate of19:2 Kbaud, the delay incurred through the mirroring operation is onlyabout five ten-thousandths of a bit.

As briefly discussed above, all signals to or from the EMP7032 are atTTL voltage levels. A trademark “NATIONAL SEMICONDUCTOR” device numberDS36276 FAILSAFE multipoint transceiver, commercially available from theNational Semiconductor Corp. of Santa Clara, Calif., is utilized on thecommunications logic board to implement a six-wire RS-485 bus throughthe provided RS-48˜bus modular connectors. In accordance with the RS-485standard, the DS36276 converts TTL voltage levels (0 to 5-Vdc) todifferential voltage levels, and vice versa. A discretely implementedMOSFET driver circuit provides interface from the communications logicboard to the KCI bus through the provided KCI bus modular connectors.The MOSFET driver circuit converts TTL voltage levels to voltage levelscompatible with the KCI standard, and vice versa. As will be understood,the interface from the communications logic board and the RS-232 serialcommunications lines is designed about a trademark “INTEL” device number8702 microcontroller, commercially available from the Intel Corporationof Santa Clara, Calif.

The 87C52 microcontroller operates at a clock rate of 11.0592 MHz, asprovided by an on-board crystal oscillator circuit. The 87C52 includesan integral UART for serial communication of RS-232 I/O to or from theEMP7032. Because, in the preferred embodiment of the present invention,the RS485 and KCI busses operate at 19.2 Kbaud and the RS-232 serialcommunications lines may operate at higher or lower data rates,depending upon the peripheral device connected thereto, buffering may benecessary, on a case-by-case basis, between the 87C52 and the EMP7032.

A trademark “HITACHI” device number HM62256 high-speed CMOS SRAMprovides 32 Kbytes of static memory for buffering between the 87C52 andthe EMP7032. Such buffering is required as many serial devices which maybe utilized operate at baud rates different form the RS-485 and KCIbusses. The serial communication lines are implemented with fourtrademark “MAXIM” device number MAX239 multi-port RS-232 drivers. APhillips Semiconductor device number SC26C94 Quad UART providesinterface between the SC26C94 and the 87C52.

Transorbs are provided on each serial communication line in and out ofthe communications logic board for protection against power surge andelectro-static discharge (ESD). Each connector further comprises aseparately fused 12-Vdc power supply connection. In the preferredembodiment of the present invention, one of the RS232 serial lines isused to connect to the battery backup system, or inverter module; threeof the KCI serial bus connectors are used to connect the percussorboard, sensor board, and scale board; and two of the RS-485 serial busconnectors are used to connect the relay board and master board.

FIGS. 17A, 17B, 17C, 17D, and 17E provide a detailed schematic drawingof the communications logic boards, fully enabling to those of ordinaryskill in the art. FIGS. 18A, 18B, 18C, 18D, 18E, and 18F provide adetailed schematic of the sensor board. FIGS. 19A, 19B, 19C, and 19Dprovide a detailed schematic of the relay board. FIGS. 20A1 and 20A2provide a detailed schematic of the infrared receiver board. FIGS. 20B1and 20B2 provide a detailed schematic of the infrared transmitter board.Each of these schematics is fully enabling to those of ordinary skill inthe art.

All software is disclosed in the software appendix, Appendix II,comprising flow charts enabling to those of ordinary skill in the art ofsoftware design and engineering. By this reference, Appendix II isincorporated herein as though now set forth in its entirety. Anexecutive summary of much of the provided function is given in thefollowing. The master board software controls 19.2 Kbaud serialcommunications to the six peripheral boards within the bariatrictreatment system. The software is responsible for initiating andterminating all serial communications. The software monitors and updatesnumerous global and local variables based upon input from the sixperipheral boards and switch inputs from the membrane switches of thecontrol units. The software also writes menu screens to a VacuumFluorescent Display (VFD) by writing display data to a register whichserves as a mailbox for another on-board processor which is tasked withupdating the VFD. The software includes menu screens for setting upvarious therapies, including rotation, pulsation, percussion, inflation,and deflation of the seat section. The software further includesdiagnostic screens for viewing error logs, software versions of softwareinstalled on the peripheral boards, membrane switch testing, mattressair hose plumbing testing, real-time clock time and date adjustments,and sensor screens for viewing the data from the peripheral boards inreal-time. The software includes switch handling code to process inputsfrom the membrane switches of the bed's swivel mounted control panel.The software includes safety features to cancel rotation due to variousbed position conditions and includes code for emulation of the standardC programming language input/output “printf( . . . );” command,including decimal, integer, and hexadecimal conversion characters.

The sensor board software controls the bed's air system directly withmotor control code for the bed's valve box, blower control code for thebed's main air blower, and therapy control code for maintaining andcontrolling therapies such as Pulsation, Rotation, Instant Inflation(INSTAFLATE), and Seat Deflate: This software also reads the analoginputs from up to 16 analog sensors and switches and utilizes theseinputs in the process of controlling the bed's multiple therapies. Suchinputs include an Auxiliary CPR Switch for shutting off the air systemin the event that serial communications with the master board areterminated. Therapies are generally, but not exclusively, controlled bythe software by comparing a set of target pressure and angle values withthe actual pressure and angle values as seen by the analog to digitalconverter, and then using various software functions to adjust the airpressures in various bladders as required. A serial protocol is includedin the software to enable 19.2 Kbaud communications by the sensor boardwith the master board.

The percussor board software controls the intensity of the percussorblower, the frequency of the percussor solenoid (which in turndetermines the frequency of percussion), and the activation of both theblower and the solenoid. The blower is controlled with a pulse-widthsignal which is generated with an internal microcontroller timer. Thesoftware includes a diagnostic mode for testing the microcontrollerports and the board's RAM. A communications time-out counter is alsoincluded in the software to provide a fail-safe response during boardoperation in cases where communications are momentarily or completelylost. A serial protocol is included in the software to enable 19.2 Kbaudcommunications by the percussor board with the master board.

The scale board software generates a 3600 Hz on-board clock pulse tostimulate two Linear Variable Differential Transformers (LVDTs) andswitch a signal rectifier. The software controls and reads the analogoutput in 16-bit digital format from an on-board Analog-to-DigitalConverter (ADC). The digital output is converted into English pounds andMetric kilograms by the master board software. A serial protocol isincluded in the software to enable 19.2 Kbaud communications by thescale board with the master board.

The relay board software provides user control of the four on-bed jackmotors for articulation of the three bed surface sections. The softwarealso provides the user with four programmed bed positioning sequencesincluding Patient Exit, Cardiac Chair, CPR, and One-Position Weighingfor the Scale. The software cooperates with the sensor board software toprovide for deflation of the bladders beneath the patient's legs duringPatient Exit. In this manner, any tendency for the patient to slidewhile exiting the bed is sharply reduced. A serial protocol is includedin the software to enable 19.2 Kbaud communications by the relay boardwith the master board. A communications time-out counter is alsoincluded in the software to provide a fail-safe response during boardoperation in cases where communications are momentarily or completelylost. Angle sensor data from the sensor board is utilized by the relayboard software to calculate the height of the head and foot sectionjack, and to calculate the Trendelenburg angle of the bed.

The high resolution angle control algorithm is implemented in the samemanner as that disclosed in U.S. patent application Ser. No. 08/672,442,filed Jun. 28, 1996, hereinabove incorporated by reference. In thismanner, a bariatric patient support system is provided that comprises afloor-engaging frame; a patient support assembly mounted to said frame,wherein the patient support assembly comprises at least twoindependently inflatable cushions; a rotational angle sensor mounted tothe patient support assembly; a microprocessor communicatively coupledto said rotational angle sensor assembly using measured angle valuesretrieved from the rotational angle sensor; and a feed back-controlledair supply operable to inflate and deflate said independently inflatablecushions in response to comparisons by said microprocessor of a set oftarget angle values with the determined angular position and angularvelocity values.

The preferred embodiment of the invention herein disclosed is designedto offer a comprehensive system of pulmonary and skin care therapies forthe critically ill, immobilized patient. Simple procedures have beendeveloped to allow the caregiver and/or patient maximum means to accessand operate the myriad functions offered. The operation of thesecontrols is substantially identical that disclosed in U.S. patentapplication Ser. No. 08/672,442, filed Jun. 28, 1996, hereinaboveincorporated by reference. The operation is summarized in Appendix I, aduplication of the Quick Reference Guide for the commercial productrepresenting the presently preferred embodiment of the inventiondisclosed herein. It is believed that this Quick Reference Guide isbeing published on a date commensurate with the filing of this presentapplication. By this reference, Appendix I, including all drawings andother parts thereof, is incorporated herein as though now set forth inits entirety.

Although the present inventions have been described in terms of theforgoing embodiments, this description has been provided by way ofexample only and is not to be construed as a limitation on theinvention, the scope of which is only limited by the following claims.Those skilled in the art will recognize that many variations,alternations, modifications, substitutions and the like are readypossible to the above-described embodiments. Only a partial sampling ofsuch variations have been pointed out herein.

1. A bariatric patient support system comprising: a frame including: afloor-engaging base frame; and a seat assembly coupled to thefloor-engaging base frame; the frame being configured such that, duringuse, the seat assembly can move vertically away from and toward thefloor-engaging base frame when a human patient weighing in excess of 500pounds is supported at least in part by the seat assembly; and at leasttwo independently inflatable bladders supported by the frame andconfigured to laterally rotate the human patient during use.
 2. Thebariatric patient support system of claim 1, where the frame furthercomprises: a head assembly pivotally coupled to the seat assembly; andat least one linear actuator coupled to the both the head assembly andthe seat assembly, and actuatable to cause a top surface of the headassembly to tilt toward a top surface of the seat assembly when thehuman patient is supported by the frame during use.
 3. The bariatricpatient support system of claim 2, where the frame further comprises: aleg assembly pivotally coupled to the seat assembly; and at least onelinear actuator coupled to the both the leg assembly and the seatassembly, and actuatable to cause a top surface of the leg assembly totilt away from a top surface of the seat assembly when the human patientis supported by the frame during use.
 4. The bariatric patient supportsystem of claim 3, further comprising: angle sensors coupled to theframe that detect one or more of (a) the angle between the head assemblyand the seat assembly, and (b) the angle between the leg assembly andthe seat assembly.
 5. The bariatric patient support system of claim 4,further comprising: a microcontroller in operable communication with theangle sensors.
 6. The bariatric patient support system of claim 1, whereeach independently inflatable bladder includes at least one internalbaffle tending to prevent that independently inflatable bladder fromassuming a cylindrical shape during inflation.
 7. A bariatric patientsupport system comprising: a frame including: a floor-engaging baseframe; a load frame coupled to the floor-engaging base frame; and a seatassembly coupled to the load frame with at least multiple linearactuators that, during use, enable vertical movement between the seatassembly and the load frame when a human patient weighing in excess of500 pounds is supported at least in part by the seat assembly; and atleast two independently inflatable bladders supported by the frame andconfigured to laterally rotate the human patient during use.
 8. Thebariatric patient support system of claim 7, where the frame furthercomprises: a head assembly pivotally coupled to the seat assembly; andat least one linear actuator coupled to the both the head assembly andthe seat assembly, and actuatable to cause a top surface of the headassembly to tilt toward a top surface of the seat assembly when thehuman patient is supported by the frame during use.
 9. The bariatricpatient support system of claim 8, where the frame further comprises: aleg assembly pivotally coupled to the seat assembly; and at least onelinear actuator coupled to the both the leg assembly and the seatassembly, and actuatable to cause a top surface of the leg assembly totilt away from a top surface of the seat assembly when the human patientis supported by the frame during use.
 10. The bariatric patient supportsystem of claim 9, further comprising: angle sensors coupled to theframe that detect one or more of (a) the angle between the head assemblyand the seat assembly, and (b) the angle between the leg assembly andthe seat assembly.
 11. The bariatric patient support system of claim 10,further comprising: a microcontroller in operable communication with theangle sensors.
 12. The bariatric patient support system of claim 7,where each independently inflatable bladder includes at least oneinternal baffle tending to prevent the respective independentlyinflatable bladder from assuming a cylindrical shape during inflation.13. A bariatric patient support system comprising: a frame adapted tosupport a human patient weighing in excess of 500 pounds during use, theframe including a longitudinal axis with the human patient will bealigned when the bariatric patient support system is used, the frameincluding: a floor-engaging base frame; a load frame coupled to thefloor-engaging base frame; and a seat assembly coupled to the load framewith at least multiple linear actuators that enable vertical movementbetween the seat assembly and the load frame; and multiple inflatablesupport cushions oriented generally transverse to the longitudinal axisof the frame; a first inflatable restraint bladder positioned generallyalong one side of the cushions, the first restraint bladder beingoriented generally parallel to the longitudinal axis of the frame; and asecond inflatable restraint bladder positioned generally along anotherside of the cushions, the second restraint bladder being orientedgenerally parallel to the longitudinal axis of the frame.
 14. Thebariatric patient support system of claim 13, further comprising: atleast two independently inflatable bladders supported by the frame andconfigured to laterally rotate the human patient during use.
 15. Thebariatric patient support system of claim 14, where each independentlyinflatable bladder includes at least one internal baffle tending toprevent the respective independently inflatable bladder from assuming acylindrical shape during inflation.
 16. The bariatric patient supportsystem of claim 13, where the frame further comprises: a head assemblypivotally coupled to the seat assembly; and at least one linear actuatorcoupled to the both the head assembly and the seat assembly, andactuatable to cause a top surface of the head assembly to tilt toward atop surface of the seat assembly when the human patient is supported bythe frame during use.
 17. The bariatric patient support system of claim16, where the frame further comprises: a leg assembly pivotally coupledto the seat assembly; and at least one linear actuator coupled to theboth the leg assembly and the seat assembly, and actuatable to cause atop surface of the leg assembly to tilt away from a top surface of theseat assembly when the human patient is supported by the frame duringuse.
 18. The bariatric patient support system of claim 17, furthercomprising: angle sensors coupled to the frame that detect one or moreof (a) the angle between the head assembly and the seat assembly, and(b) the angle between the leg assembly and the seat assembly.
 19. Thebariatric patient support system of claim 18, further comprising: amicrocontroller in operable communication with the angle sensors.